Question 197859
 I need help simplifying √4x^2/4b
{{{sqrt(4x^2)/4b}}}
= 2x/4b
= x/2b
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and solving (2+√5)(4-√10) 
There's nothing to solve for.
It can be multiplied
{{{(2+sqrt(5))*(4-sqrt(10))}}}
= {{{8 -2sqrt(10) + 4sqrt(5) - 2sqrt(5)}}}
= {{{8 - 2sqrt(10) + 2sqrt(5)}}}